The prior art discloses a number of improvements in combustion and plasma arc flame spray guns of the type through which heat fusible inorganic metal and ceramic or refractory wire or rod is fed, heat softened, atomized into molten droplets or particles projected onto a substrate to provide a coating thereon for various well known purposes and applications such as disclosed in U.S. Pat. No. 2,707,691 granted to Wheildon.
Heretofore, many attempts have been made to remedy a number of problems associated with flame spray guns. One such problem concerns itself with the air driven turbine and means regulating the speed thereof and hence the feed of the wire or rod at a relatively constant rate into the flame.
Another problem arises from improper mixing of the oxidant, fuel gas and the compressed air due to leakage by seals and hence between ports in the main supply valve and the flame spray nozzle. The result of which causes fluctuations in flame temperature and the supply of compressed air to drive the wire or rod feed turbine mechanism and to propel the molten droplets of the rod onto the substrate.
Thus, the object of the instant invention is to provide a more reliable and stable spray gun with improved supply valve means, flame spray nozzle means, sealing means, air turbine drive means and air turbine speed and feed regulating means.